A stable low noise and high gain dual‐band active band‐pass filter with GaAs‐MESFET using CRLH metamaterial

In this article, a stable low noise and high gain dual‐band active bandpass filter (BPF) with GaAs‐metal‐semiconductor field effect transistor (MESFET) using composite right‐/left‐handed (CRLH) metamaterial is presented. The CRLH approach in a microstrip structure is applied to develop a dual‐band BPF using an amplifier circuit with two arbitrary frequency bands. The two center frequencies of the filter are then chosen as ω 1  = 1.23 GHz and ω 2  = 1.63 GHz, where the phase slope characteristics of the response are chosen as −90° and −270° at frequencies of ω 1 and ω 2 , respectively. The experimental results show gain values of 7.82 and 7.03 dB and the return losses of −15.1 and −10.1 dB with bandwidth of 55 (4.4%) and 105 MHz (6.4%) at the center frequencies of 1.22 and 1.61 GHz, respectively. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1985–1988, 2014